System-independent quantitative cardiac CT perfusion Summary BioInVision, Inc. and Case Western Reserve University researchers will develop software for quantitative anal- ysis of cardiac CT perfusion (CCTP), creating an important tool for evaluation of cardiovascular disease. With this product, cardiologists will be able to identify functional flow deficits in coronary artery territories. When one combines functional myocardial blood flow (MBF) with coronary anatomy from computed tomography angi- ography (CTA), it provides needed information on the physiologic significance of a stenosis. The CTA+CCTP combo could provide an ideal gateway exam for deciding whether to send a patient for percutaneous invasive coronary angiography and potential intervention (e.g., stenting). In addition, if flow is low and no stenosis is present, it will suggest microvascular disease, a very prevalent ailment of growing concern, especially among women and in diabetes. CT compares favorably to all other non-invasive cardiovascular imaging techniques (SPECT, PET, and MRI). It is available in many settings, including emergency departments. It provides both MBF and reliable coronary anatomy, not available in any other single modality. It has excellent resolution ena- bling detection of endocardial perfusion deficit, thought to be an early disease indicator that is impossible to assess with SPECT. CT is cheaper and has higher patient throughput than MRI or PET. With inclusion of MBF, CT would have an excellent opportunity to disrupt the diagnostic pathway leading to percutaneous intervention, a pathway now dominated by SPECT myocardial imaging, which includes zero information about coronary anatomy. To achieve reliable, accurate CT MBF measurements, we will invoke innovations to reduce beam hardening and to make reliable estimates of flow. Currently, CT perfusion is done on different CT machines with manufacturers? proprietary software, using algorithms that can give erroneous MBFs. Applicable to any commercial scanner; our solution would harmonize measurements across acquisition systems providing trust- worthy, standardized measurements to clinicians, thereby improving management of cardiovascular patients.